La prueba del algodón del alarmista climático

Siempre buscando la prueba del algodón. ¿Tienen razón los alarmistas del calentamiento global?

Hasta el momento no han ofrecido nada a lo que ni siquiera ellos mismos se atrevan a llamar “prueba”. Lo que dicen es que han hecho una “atribución”, que quiere decir que deducen que la mayor parte del calentamiento observado entre 1975 y 2000 es por el CO2 que hemos emitido. Y el razonamiento subyacente es que el CO2 es la mejor explicación que pueden ofrecer.

Pero que sea la “mejor explicación” no implica que sea una buena explicación, ni tan siquiera que sea válida. También significa que estamos jugando con una especulación (la “atribución”), y lo razonable es que le hagamos a esa especulación el caso que merece. Buscar la prueba del algodón es buscar eso; el caso que merece.

Aquí hay un buen ejemplo, y los próximos años son clave. Se llama Estado del clima en 2008, y está publicado por la NOAA (National Oceanic and Admospheric Administration), la agencia federal de meteorología USA. Uno de los capítulos trata precisamente del “problema” de que en la última década no está habiendo calentamiento, y de si eso desdice los modelos en los que se basa la alarma climática.

The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.

Saco de Girma Orssengo, en lo de Curry, los datos de los últimos 13 años [–>]:

• Year=>GMTA (deg C)
• 1. 1998=>0.53
• 2. 1999=>0.30
• 3. 2000=>0.28
• 4. 2001=>0.41
• 5. 2002=>0.45
• 6. 2003=>0.47
• 7. 2004=>0.44
• 8. 2005=>0.47
• 9. 2006=>0.42
• 10. 2007=>0.40
• 11. 2008=>0.33
• 12. 2009=>0.44
• 13. 2010=>0.47

Datos:

Para los que quieran profundizar con la fuente de la prueba del algodón, dejo los datos y copio el artículo en el que vienen:

NCDC / NOAA:

Do global temperature trends over the last decade falsify climate predictions? —J. KnigHT, J. J. KEnnEDy, C. FoLLanD, g. HarriS, g. S. JonES, M. PaLMEr, D. ParKEr, a. SCaiFE, anD P. SToTT

Página 22 de:

• State of Climate in 2008.

El Niño–Southern Oscillation is a strong driver of interannual global mean temperature variations. ENSO and non-ENSO contributions can be separated by the method of Thompson et al. (2008) (Fig. 2.8a). The trend in the ENSOrelated component for 1999–2008 is +0.08±0.07°C/decade, fully accounting for the overall observed trend. The trend after removing ENSO (the “ENSO-adjusted” trend) is 0.00°±0.05°C/decade, implying much greater disagreement with anticipated global temperature rise.

We can place this apparent lack of warming in the context of natural climate fluctuations other than ENSO using twenty-first century simulations with the HadCM3 climate model (Gordon et al. 2000), which is typical of those used in the recent IPCC report (AR4; Solomon et al. 2007). Ensembles with different modifications to the physical parameters of the model (within known uncertainties) (Collins et al. 2006) are performed for several of the IPCC SRES emissions scenarios (Solomon et al. 2007). Ten of these simulations have a steady long-term rate of warming between 0.15° and 0.25ºC/decade, close to the expected rate of 0.2ºC/decade.ENSO-adjusted warming in the three surface temperature datasets over the last 2–25 yr continually lies within the 90% range of all similar-length ENSO-adjusted temperature changes in these simulations (Fig. 2.8b). Near-zero and even negative trends are common for intervals of a decade or less in the simulations, due to the model’s internal climate variability. The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.

The 10 model simulations (a total of 700 years of simulation) possess 17 nonoverlapping decades with trends in ENSO-adjusted global mean temperature within the uncertainty range of the observed 1999–2008 trend (−0.05° to 0.05°C/decade). Over most of the globe, local surface temperature trends for 1999–2008 are statistically consistent with those in the 17 simulated decades (Fig. 2.8c). Field significance (Livezey and Chen 1983) is assessed by comparing the total area of inconsistent grid boxes with the range of similar area values derived by testing the consistency of trends in each simulated decade with those in the remaining simulated decades. The 5.5% of the data area that is inconsistent in the observed case is close to the median of this range of area values, indicating the differences are not field significant. Inconsistent trends in the midlatitude Southern Hemisphere strongly resemble the surface temperature pattern of the negative phase of the SAM (Ciasto and Thompson 2008), which did indeed show a negative trend in the last decade.

These results show that climate models possess internal mechanisms of variability capable of reproducing the current slowdown in global temperature rise. Other factors, such as data biases and the effect of the solar cycle (Haigh 2003), may also have contributed, although these results show that it is not essential to invoke these explanations. The simulations also produce an average increase of 2.0°C in twenty-first century global temperature, demonstrating that recent observational trends are not sufficient to discount predictions of substantial climate change and its significant and widespread impacts. Given the likelihood that internal variability contributed to the slowing of global temperature rise in the last decade, we expect that warming will resume in the next few years, consistent with predictions from near-term climate forecasts (Smith et al. 2007; Haines et al. 2009). Improvements in such forecasts will give greater forewarning of future instances of temporary slowing and acceleration of global temperature rise, as predicted to occur in IPCC AR4 projections (Easterling and Wehner 2009).